1. Field of the Invention
The present invention relates to an absorption chiller-heater, particularly relates to an absorption chiller-heater of a multi heat source drive type having an exhaust heat fired regenerator constituting a heat source by exhaust heat and a directly fired regenerator constituting a heat source by combustion heat of a burner.
2. Related Art
According to an absorption chiller-heater of a multi heat source drive type having an exhaust heat fired regenerator constituting a heat source by exhaust heat and a directly fired regenerator constituting a heat source by combustion heat of a burner, in order to achieve energy conservation performance, normally driving by utilizing exhaust heat is predominantly carried out. For example, in an air conditioning system, when air conditioning is requested, first, the absorption chiller-heater is driven by the exhaust heat fired regenerator by utilizing exhaust heat and when a heat amount of exhaust heat is insufficient relative to an air conditioning load, the absorption chiller-heater is driven by combusting the burner of the directly fired regenerator. At this occasion, in order to control to combust the burner in correspondence with a load of the air conditioning load or the like, the burner is controlled to combust in accordance with temperature of a heat medium cooled or heated by an evaporator of the absorption chiller-heater, that is, temperature of the heat medium in an outlet portion from the evaporator of a heat medium passage in which the heat medium flows.
Here, when the load of the air conditioning load or the like is large, there is a case in which a heat input amount of the absorption chiller-heater becomes excessive since two generators of the exhaust heat fired regenerator and the directly fired regenerator are driven. Further, there is a case in which the heat input amount becomes excessive when a deficiency in the input heat amount at the exhaust heat fired regenerator is supplemented by the directly fired regenerator and the exhaust heat amount which has been reduced is increased or the like. In such a case in which the heat input amount becomes excessive, when the burner is controlled to combust in accordance with temperature of the heat medium at the outlet portion from the evaporator of the heat medium passage, the burner is continued to drive until temperature of the heat medium becomes lower than predetermined temperature even when the input heat amount becomes excessive. Therefore, there is a possibility of posing a problem in reliability of the absorption chiller-heater such that the temperature of the exhaust heat fired regenerator or the directly fired regenerator is excessively elevated, the temperature of the regenerator becomes abnormal, operation of the absorption chiller-heater is stopped or an absorbent solution in the exhaust heat fired regenerator or the directly fired regenerator is excessively condensed to crystallize by which a member constituting the regenerator is liable to corrode and a frequency of maintenance operation is increased or the like.
There is proposed an absorption chiller-heater of a multi heat source drive type having an exhaust heat fired regenerator and a directly fired regenerator, including detecting device for detecting temperature of the directly fired regenerator in order to prevent excessive rise of temperature of the regenerator brought about by simultaneously driving the exhaust heat fired regenerator and the directly fired regenerator in starting, wherein when the temperature detected by the detecting device becomes a previously set temperature, combustion of a burner of the directly fired regenerator is stopped to thereby restrict a heat input amount (for example, refer to JP-A-6-281288 (pages 2–3, FIG. 1)).
However, according to JP-A-6-281288, there is prevented the excessive rise of the temperature of the exhaust heat fired regenerator or the directly fired regenerator brought about by simultaneously driving the exhaust heat fired regenerator and, the directly fired regenerator in starting in ordrer to shorten a time period of starting the absorption chiller-heater. Further, a premise is constituted by the fact that 100% of an exhaust heat amount is necessarily present and therefore, no consideration is given to control of heat input amounts to the respective regenerators when the directly fired regenerator is simultaneously driven in order to supplement a deficiency in the heat input amount to the exhaust heat fired regenerator in normal operation.
Further, in the case in which the burner of the directly fired regenerator is assumedly controlled to combust and stop as in JP-A-6-281288, when a heat amount of exhaust heat or the load of the air conditioning load or the like is varied, the burner of the directly fired regenerator is controlled to combust and stop to combust by outlet temperature of the heat medium from the evaporator and temperature of the directly fired regenerator and therefore, there is a case in which the burner of the directly fired regenerator is repeatedly combusted and stopped to combust. Therefore, there is a case of bringing about a state in which the temperature of the directly fired regenerator or the like is excessively elevated intermittently, operation of the regenerator by abnormal temperature of the regenerator cannot be restrained from being stopped or crystallization of the absorbent solution, corrosion of the regenerator or the like cannot be restrained from being brought about and reliability of the absorption chiller-heater cannot be promoted.